Trulock TRU-Choke Sd Pattern Plus 12 Ga Light Modified The Pattern Plus Style Choke Tubes Fit Flush With The End Of The Barrel. They Are manufactured From High Strength 17-4 Ph Stainless Steel And Are Marked On The Body With The Degree Of Choke as Well as The Exit Diameter. They Are The Choice For Those Shooters Who Want a High Quality Choke Tube But Prefer a Flush Mount Style.